The following abbreviations are herewith defined, at least some of which are referred to within the following description about at least the prior art and/or the present invention.    1× EV-DO 1× Evolved-Data Optimized    3GPP2 Third Generation Partnership Project 2    AN Access Network    AT Access Terminal    BSC Base Station Controller    BTS Base Transmitter Station    CDMA Code Division Multiple Access    MCTA Multi Carrier Traffic Allocation    RNC Radio Network Controller    THOLD Threshold
A wireless telecommunication system (e.g., CDMA cellular radio system) has multiple access nodes (e.g., BSC, RNC) each of which manages multiple radio sites (e.g., BTSs). Each radio site has a certain set of frequencies F1, F2, F3 etc. . . . where access terminals (ATs) idling in that particular radio site will be distributed among those frequencies F1, F2, F3 etc. . . . In particular, the ATs when requesting a connection setup with the corresponding access node (e.g., BSC, RNC) will always request to use a particular frequency F1 (for example) known as an “originating frequency” on which they are idling. The corresponding access node (e.g., BSC, RNC) would always assign resources for the connection setup on the originating frequency (e.g., F1) which may cause an undesirable load imbalance among the frequencies F1, F2, F3 etc. . . . resulting in different levels of contention and user experiences. To address this particular drawback, the access node has been enhanced to implement a traffic allocation technique (e.g., Multi Carrier Traffic Allocation (MCTA) technique) which uniformly allocates the AT's traffic across the radio site's frequencies F1, F2, F3 etc. . . . (co-located frequencies) and even another radio site's frequencies F4, F5, F6 etc. . . . (non co-located frequencies).
In the traffic allocation technique, the AT can attempt to secure the air connection on one radio frequency (e.g., originating frequency) but be redirected to another collocated or non co-located radio frequency (e.g., target frequency) if the access node determines that the loading conditions warrant changing the AT from the originating frequency to the target frequency. The newly assigned target radio frequency can be in the same or different frequency band to that of the originating frequency. However, the radio characteristics of the new target frequency can be quite different from the originating frequency and hence the probability of a failed connection rises significantly with this type of cross-frequency traffic allocation. An exemplary list of some of the reasons why the probability of a failed connection can rise significantly when the access node's traffic allocation technique directs the AT to switch from the originating frequency (e.g., F1) to the target frequency (e.g., F2) are as follows:                Frequency selective fading could make radio conditions on the originating frequency and the assigned target frequency significantly different in any given location within the radio-site.        Interference characteristics from surrounding radio sites (cells) may vary between the originating frequency and the assigned target frequency due to different traffic/load levels.        Significant coverage differences can exist in the radio site between the originating frequency and the target frequency when the AT's traffic is re-directed across different frequency bands.        The radio site's equipment installations such as the feeder paths and antenna locations on the tower can be different for the originating frequency and target frequency and this difference can lead to further changes in coverage footprints even when the originating frequency and target frequency are collocated frequencies or in the same frequency band. For example, antennas that transmit down link signals to the AT may be different physical entities on the tower which would add spatial de-correlation to the list of differences in radio channel conditions.        
In addition to the above drawbacks, in CDMA (3G.PP2) cellular radio systems there is no provision for the ATs to measure potential target frequencies prior to switching to the target frequency, when requesting a traffic channel during a connection origination. Hence, the AT when instructed to change from an originating frequency to a target frequency is essentially blind to the target frequency's radio conditions. Thus, it can be appreciated that the traffic allocations technique of re-directing an AT from the originating frequency is inherently prone to connections failures, which presents a difficult trade-off against the uniform traffic distribution benefit of the traffic allocations technique. Accordingly, there has been and still is a need to address the various shortcomings associated with the access node's traffic allocation technique redirecting the AT from an originating frequency to a target frequency. These needs and other needs are satisfied by the present invention.